Exam 2

Cell Membrane & Transport

• Phospholipid Bilayer: Controls what enters and exits the cell; hydrophobic tails prevent water-soluble substances from passing freely.

• Basic Organelles:

  • Nucleus: DNA storage, control center.

  • Mitochondria: Energy production (ATP).

  • Ribosomes: Protein synthesis.

  • Endoplasmic Reticulum (ER): Smooth ER (lipid synthesis), Rough ER (protein processing).

  • Golgi Apparatus: Modifies, sorts, and ships proteins.

  • Lysosomes: Digestion and waste removal.

  • Peroxisomes: Detoxification.

Types of Transport

• Simple Diffusion: Movement of molecules from high to low concentration (no energy needed).

• Facilitated Diffusion: Uses transport proteins for larger molecules (no energy needed).

• Passive Transport: General term for diffusion/osmosis (no energy needed).

• Active Transport: Moves molecules against the concentration gradient (requires ATP).

• Osmosis: Water movement through a semipermeable membrane to balance solute concentration.

• Endocytosis: Cell engulfs material (phagocytosis = solids, pinocytosis = liquids).

• Exocytosis: Cell expels material using vesicles.

Osmotic Pressure & Tonicity

• Osmotic Pressure: Water moves to areas with more solutes.

• Hypertonic Solution: Higher solute concentration outside cell → cell shrinks (crenation).

• Hypotonic Solution: Lower solute concentration outside cell → cell swells/bursts (lysis).

• Isotonic Solution: Equal solute concentration → no net movement of water.

Epithelial Tissue Locations

• Simple Squamous Epithelium: Lungs (alveoli), blood vessels (capillaries).

• Simple Columnar Epithelium: Digestive tract (small intestine, stomach lining).

• Stratified Squamous Epithelium: Skin, esophagus, mouth, vagina.

• Transitional Epithelium: Bladder, ureters (allows stretching).

Glands

• Endocrine Glands: Secrete hormones into the bloodstream (e.g., thyroid, adrenal).

• Exocrine Glands: Secrete substances through ducts (e.g., sweat, salivary glands).

Connective Tissue

• Cells of Connective Tissue:

  1. Fibroblasts – Produce fibers & ground substance.

  2. Macrophages – Engulf pathogens/debris.

  3. Mast Cells – Release histamine (inflammation).

  4. Adipocytes – Store fat.

  5. Chondrocytes – Found in cartilage.

  6. Osteocytes – Found in bone.

• Protein Fibers in Connective Tissue:

  1. Collagen Fibers – Strong & flexible (tendons, ligaments).

  2. Elastic Fibers – Stretchy (skin, lungs, arteries).

  3. Reticular Fibers – Supportive framework (lymph nodes, spleen).

Layers of the Epidermis (Superficial to Deep)

1. Stratum Corneum – Dead, keratinized cells.

2. Stratum Lucidum – Only in thick skin (palms, soles).

3. Stratum Granulosum – Produces keratin.

4. Stratum Spinosum – Strength & flexibility.

5. Stratum Basale – Cell division, melanocytes, and stem cells.

Histology (Slide Identification)

• Pseudostratified Epithelium: Found in respiratory tract (trachea, bronchi).

• Skeletal Muscle: Striated, voluntary, multinucleated.

• Adipose Tissue: Stores fat, insulation, energy reserve.

• Bone Tissue: Rigid matrix, osteocytes in lacunae.

• Cartilage Tissue: Flexible support, chondrocytes in lacunae